The volume pot on the sub is probably just used for balancing the sub to the mains, not as a system master control. How are you gong to drive the sub, from low-level inputs or speaker level? Are you using a preamp to drive the SSE?

It sounds like you have a pot on your SSE and want to control the subwoofer with the same pot. As the previous poster alluded to, you would normally do this with your preamp (or passive volume control).

If you don't have one, what you could do is add a pair of RCA jacks to the SSE that taps into the output of your volume control between the pot and PCB. Then you have a volume-controlled output that you can use to drive the sub.

Thanks for the replies. I won't be using a preamp. I want to add a pot to the sse to have some control over the vol of the sub. As you well know, some recordings need a little bass boost and some don't. I think what Russ is describing is what i want to do with a separate pot. When i get the sub i will see how it is set up and go from there.
Roy

Which Subwoofer? I just got one of the cheap Polk Audio 10 inch powered sub from Newegg. Haven't made it work yet, but I haven't had time to try. Just got home from work and its 9PM.

There is no simple answer to this question. It depends of the source and the sub. The ideal case would be a low impedance source and a sub with a high impedance line input. In this case you wire the input to the sub directly across the input terminals on the Simple SE PC board after the volume pot. If this causes non linear action of the volume control then a volume pot with a lower resistance may be required, but too low of a resistance may upset your source.

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In this case you wire the input to the sub directly across the input terminals on the Simple SE PC board after the volume pot.

I've done this myself except my volume control is external to the amp in case I want to swap it out. The only issue I've found is that plugging in the sub reduces my usable gain enough to be annoying with wimpier sources (ipod, my single opamp phono stage, etc).

At some point I'd like to build have a line stage to take the punishment of this arrangement. Or even better an active crossover to move all the low frequencies to the sub.

I got the Polk because Newegg sent me a cupon code so I got it for $89 with free shipping. As with the Polk, the specifications listed on the Yamaha web site are rather sparse. There is no mention of the line level input impedance. Yamaha wants me to register on their web site to see the owners manual, so I didn't look there. Maybe the specs are in the manual.

Quote:

At some point I'd like to build have a line stage to take the punishment of this arrangement. Or even better an active crossover to move all the low frequencies to the sub.

I have decided that the line stage is what I need long term. The sub has a low pass filter already so it will only respond to the low frequencies. At least with my setup I don't see any problems with letting the full audio range hit the Simple SE or Simple P-P. The speakers that I use (and most small speakers) have an impedance curve that is above 8 ohms from 35Hz to 120 Hz. This keeps the OPT from saturating unless I get crazy with the volume knob. I believe that inserting any more frequency response shaping devices into the audio chain will only hurt the sound. They tend to alter the phase response over a fairly wide range.

The system that I listen to most often is also the system that I use for testing and experimenting. This is a pain because I have to disconnect the amp that I listen to in order to hook up an amp for testing. I already have a 3 way switch for the speakers that works good, but switching the source has been problematic. I need to switch between 4 or 5 sources, and 4 or 5 possible outputs with more than one output active at once (amps, computer, test bench, and now the sub). The push button switch box from Radio Shack does not belong in a quality audio chain (snap, crackle, pop, and even hiss). I would like the ability to A/B two amps with the push of a button. The solution seems to be a line stage with multiple independent outputs.

I have done some experimentation, yielding promising results, but no activity has taken place in several months. I plan to get back to this soon since I now have a new sub that sits disconnected.

The concept is a tube buffer with multiple inputs switched by sub miniature relays. It feeds 5 seperate buffers so that each output is completely independent. Shorting an output or connecting it to a complex load will not affect the other outputs. Each output has its own level control. My initial experiments used a CCS loaded cathode follower for the buffer and 5 seperate mosfet followers for the buffers. It worked good and had a flat frequency response past 1 MHz (my measurement limit). It however needed some gain so I plan to experiment further in the near future.

__________________
Tubelab, it's 5 year mission. To explore strange new tubes, to seek out new circuits and topologies, to boldly go where no tube has gone before......

I have a half-finished preamp sitting in a box. I've learned a great deal since starting that project almost 10 years ago. I used it in it's unfinished state for a while, but took it apart while building the logic board. I got my hands on a nice cache of mercury-wetted SPDT relays and that is what drove the rest of the design. I too am using a crunchy Rat-Shack push-button selector right now

The preamp itself is a 4-channel preamp (mu followers) with an extra 2-channel buffered output (cathode followers). It was all done with 12AU7s because that was the only tube I had on hand in any quantity back then (from my old organ). The PSUs, amps, relays, and logic board are all crammed in one chassis. The plan now is to remove or disable the preamp and make it into a passive selector/volume control. That way I can play around with preamps without have to take my whole system apart each time.

I haven't broken down and bought a sub yet. The KLF-10s have amazingly deep bass and I just don't feel like I'm missing anything.